As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 3319, CREW REPORTED ON TAKEOFF, COCKPIT FILLED WITH SMOKE. DECLARED AN EMERGENCY AND RETURNED TO DEPARTURE. AIRCRAFT LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. REMOVED AND REPLACED NR 1 ENGINE IAW W/C 71-000-00, NO LEAKS OR SMOKE NOTED AT THIS TIME. ALL PARAMETERS NORMAL. AIRCRAFT RETURNED TO SERVICE. THE CAUSE OF THE SMOKE WAS FOUND TO BE A FAULTY NR 4 CARBON SEAL.